This invention relates generally to tone arm mechanisms for record players, and more particularly the present invention relates to a mechanism for vertically raising and lowering the tone arm and to a circuit arrangement for detecting the vertical position and/or the status of the tone arm.
In most conventional record players or the like, the tone arm carrying a pickup cartridge with a stylus is moved up and down by using a rotational force from the driving motor operatively connected to the turntable of the record palyer. Namely, the tone arm is raised or elevated from its rest by elevating a member which is usualy called a tone arm elevator, and then the tone arm is swung horizontally to be moved to a given position above a phonograph record, and then the tone arm is lowered so that the stylus thereof is correctly positioned on a given position of the sound grooves of the record disk. After playing the record disk, similar operation is performed to return the tone arm to the rest. However, in such conventional devices, a complex mechanism is required for applying the rotational force of the motor to the tone arm in the form of a reciprocating force. Although there is another conventional tone arm elevating mechanism, in which an additional motor is provided for operating the tone arm in vertical directions, the same problem as the above has been inevitable. Meanwhile, there is a tendency that various mechanical devices are replaced by electrically operated devices in connection with various devices, such as tape recorders, record players or the like. Electrically operated and/or controlled devices are now getting popular because such an electrically operated devices are easy in manipulation, simple in construction, and accurate in operation. Furthermore, such an electrically operated devices usually occupy less space than pure mechanical devices.
Under these circumstances, the inventor of the present invention had an idea of using a solenoid as a driving means of the tone arm, so that an elevator which is located below the tone arm is raised and lowered in accordance with the reciprocating movement of the plunger of the solenoid. However, when a solenoid were simply applied, desired control of the tone arm would not be expected because the plunger of the solenoid instantaneously moves back and forth, applying an undesirable shock or impact to the tone arm. In other words, when a reciprocating force of the solenoid plunger is directly applied to the tone arm, the tone arm is apt to jump up when elevating the same, resulting in deviation of the stylus from a desired position. Similarly, if the lowering operation of the tone arm is simply controlled by such a solenoid, the stylus might be roughly dropped on the record disk, damaging the stylus as well as the record disk.
Apart from the above problem, it is necessary to accurately detect the vertical position and the state of the tone arm in order to electricaly control various operations of the tone arm, such as horizontal movement thereof and antiscating.